Process of metallizing with precious metals.



(UNITED STATES PATENT, OFFICE;

, RUDOLF LANGHANS, OF BERLIN, GERMANY.

SPECIFICATION forming part of Letters Patent No. 666,321, dated January 22, 1901.

' Application filed June 23.1900. ge m No. 21,2 4." on a as.)

To ctZZ whom it may concern:

Be it known that I, RUDOLF'LANGHANS, a subject of the Emperor of Austria-Hungary, residing at No. 6 An-der-Stadtbahn, Berlin, Prussia, German Empire, have invented a new and useful Improved Process of Metalli-zing with Precious Metals; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to the metallizing of objects with precious metals; and it provides for an improved process by the aid I of which objects of'any kind, shape, and substance (both inorganic and organic) can be metallized, both entirely and partly, with precious metals in a by far more advantageous and simpler manner than heretofore. Especially, my present invention is adapted for metallizing with platinum and other metals of ,-the platinum group, with mixturesor alloys of such metals,with gold, and with mixtures or alloys of gold with one or more of the metals of the platinum group.

The base of my present invention is the use of certain organiccomp'ounds of precious metals-that is to say, those compounds which sulfur derivatives of the aliphatic series form with precious metals and with halogen (chlorin, bromin, and iodin) compounds of precious metals, such as compounds of the'sulfur derivatives of the alcohol radicals, (mercaptans, sulfids', alkyldisulfids, and socalled sulfin compounds,) of the sulfur derivatives of the aldehydes, (thioaldhydes, mercaptals,) and of the sulfurderivatives of r the ketones (thioketones, 'mercaptols) with halogen (chlorin, bromin, and iodin) compounds. of precious metals, or with'free or pure precious metals, as also hydroxids, nitrites, and nitrates of such of said com pounds as are formed with the free or pure precious metals. (For composition, preparation, &c., see, for instance, Bevllstetn,tHandbuch dcr Orgomt'schen Che mic, first tome, third edition, pages 347to 369-.) Up to the present invenl tion the; said metalliferous aliphatic sulfur derivatives have not found any use in the arts, but were of a mere scientific "interest only. New I have discovered that they possess properties which make them very well adapted for the purpose in view. They melt at a comparatively low temperature, and in the molten state'they form an oily fluid which, being mobile, allows to be very regularly and uniformly distributed over surfaces of the finest configuration. A slight raising of the temperature of the fluid suffices to cause its reduction to metal, and as this reduction takes place slowly and progressively the metal is separated'outin the state of a homogeueousand dense deposit, showing a brilliant mirror-like surface. The metallic depositis Well coherent in 'itself and adherent to the foundation, so that it does not allow to be'removed by rubbing, but can be burnished. Moreover,it .is perfectly stable, whereby is meant that it does not transform into the state of black or sponge as, for instance, do the metallic deposits produced by means of ethyl platinum chlorid,hydrogen platinum 'cyanid, and the like. Besides, the deposit can easily be Welded vby means; of a Bunsen flame fed with gas under pressure. On the other hand, the gaseous products of decomposition containing chlorin and sulfur do'not in the least attack the substance to be metallized'. For

metallizing with gold a temperature of 50 to 150 centigrade will suifice, whereas with metals of the platinum group a temperature of 150 to 350 centigrade is required.

By virtue of the above properties of the "compounds specifiedI am enabled to metallize even objects made out of a combustible materialsuch, for instance, as paper, fab rics, and other fibrous structures-without damaging such foundation; butI am also enabled to burn away a combustible foundation, so that the pure metal is leftbehind as a .true imitation of the combustible founda- "tion. For instance, I am enabled by my present invention to transform the well-known fibrous foundation for manufacturing incandescent mantles into a mantle composed of gold or of one or more metals of the platinum group orof any alloy of gold and such metalsea problem not hitherto resolved; but I may as well coat a refractory surfacefor instance,one of glass, porcelain, and the likewith a brilliant mirror of gold, platinum,

iridium, and the like; I

From what is said it results that my presentinvention essentially consists in wetting means of argentic nitrate.

cause decomposition of the metallizing complatinum mirror thus obtained may finally be the object to be metallized with a solution of one or more of the said met-alliferous aliphatic sulfur derivatives prepared with a volatile or volatilizable solvent, allowing the solvent to volatilize, wetting anew with the fluid, if required, heating up to the meltingpoint of the compoundor mixture of compounds used, and finally raising the temperature above the decomposition-point of said compound or mixture of compounds.

If the object to be metallized is made out of a combustible material-as, for instance, pa per, wood, fibers, and the like-and it is not desired to destroy such foundation, the tempcratu re is raised only so much as required to pound used, whereas when the shaped combustible foundation is intended to merely serve asa model, form, or mold, so tospeak, such a degree of heat is applied as willcause the fabric or other combustible material or structure used as the foundation to bur away. v

. I wish it to be understood that the terms metallizing and wetting as used in the present specification and the annexed claims are intended to comprise the former, coating with metal, impregnating with metal, and transforming into metal, and the latter coating, painting, impregnating, or in any other wise providing the object or foundation with the solution of the metallizing compound or compounds.

I Of the'metallizing compounds cited I at present prefer as the most advantageous ones those of the radicals of the fatty alcohols, especially their sulfids, (so called sulfin salts,) and in all cases where a combustible foundation is not to be destroyed. I prefer to use the ethyl sulfid platinum chlorid and protochlorid, whereas when the foundation is to be burned away I prefer the nitrates obtained from the said halogen'compounds by As solvents may be used volatile liquid hydrocarbons, alcohol, chloroform, and the like.- I, however, prefer to employ bromoform, as this solvent allows highly-concentrated solutionsto be prepared' In order that my invention may be fully understood, I proceed to describe some exam ples of how to reduce it to practice.

First. Productionsof mirrors, specula, and reflectors.A refractory back-for instance, a concave parabolically-shaped back out of porcelain-is carefully freed from any adhering impurities, coated, as by painting with a penoil, with a. bromoformic solution of ethyl sulfid platinum chlorid and the bromoform allowed to volatilize, when the coated back is first gently heated up to themelting-point of the coating and then the temperature raised above the decomposition-point of the coating. When the decomposition is complete,the back shows to be covered with a very uniform and brilliant coherent layer of platinum. The

burned in by raising the temperature up to a red heat.

Second. Production of meiallized folia, for instance, for use in galvanic gas-batteries.- Sheets of paper, asbestos, or slate are wetted with a bromoformic solution of ethyl sulfid platinum chlorid and the hromoform allowed to volatilize, when heat is applied first gently up to the melting-point of the chlorid and finally to its decomposition-point. In case of sheets of paper or cardboard being used as the foundation, if such foundation is intended to be left unaltered, so as to produce, for instance, paper sheets impregnated with platinum, the final heat has to be such as will not cause the paper to be ca'rbonizedthat is to say, the final heat applied should not be higher than 300 centigrade.

Third. Production of blanks for rapid ielegraphy..'lhe signs to be transmitted are written upon a non-conductive sheet--for instance, a sheet of paper or cardboard using the solution of the metallizing compound as the ink and a pen made out of platinum or iridium as the writing instrumentthe signs are allowed to perfectly dry, and then the sheet is passed through a pair of cylinders heated up to the decomposition-pdint of the metallizing compound-for instance, ethyl sulfid platinum chlorid. On leaving the cylinders the sheet shows to be provided with metallic signs, which extend through the pa- .per from one side to the other;

Fourth. Transformation of fibrous Struc-- fures into pure metallic ones.A combustible structure-for instance, the fabric used for manufacturing incandescent mantles-is impregnated with a bromoformi'c solution of nitrated ethyl sulfid platinum, (obtained by mixing a solution of ethyl sulfid platinum protochlorid with argenticnitrate and filtering,) the impregnated fabric is placed on the mold and allowed to dry, and when perfectly dry it is burned as in manufacturing incandescent mantles, whereby the structure is caused to shrink more or less, according as pressed or chased, hammered, and burnished.

Fifth. Production of small metal tubes for manufacturing filaments for electric incandescent lamps.A well-polished artificial IIO threadfor instance, a threadproduced froth heated above the decomposition-point of the mtallizingcompound to such a temperature as will destroy the cellulose thread or foundation.

am mums a'tunmmtzn ttsaeiuuts search Home Obviously my invention may also be used ito replace the well-known preparations of precious metal with balsam of sulfur.

What I claim as my invention is1- 1. The process of metallizing with precious metals which consists in wetting a foundation with a solution of a compound or compounds of precious metals with aliphatic sulfur derivatives prepared with a volatile solvent, drying, heating first up to the melting-point of the metallizing compounds, and thenraising the heat above the decomposition-point of said compounds, substantially as and for the purpose specified.

2. The process of metallizing with precious metals which consists in wetting a foundation with a bromoformic solution of a compound or compounds of precious metals with aliphatic sulfur derivatives,drying, heating first up to themelting-point of the said metallizing compound or compounds, and then raising the temperature above the decom positionpoint of the said compound or compounds, substantially as and for the purpose specified.

3. The process of metallizing with precious metals which consists in wetting a foundation with a solution of precious metals compounded with sulfids of aliphatic alcohol radicals, drying, and heating, substantially as described.

4. The process of metallizing with precious metals which consists in wetting a combustible foundation with a solution of precious metals compounded with sulfids of aliphatic alcohol radicals, drying and heating, substantially as described.

5. The process of metallizing with precious metals which consists in wetting a porouscombustible foundation with a solution of precious metals compounded with sulfids of aliphatic alcohol radicals, drying and heating, substantially as and for the purpose described.

6. The process ofmetallizing with precious 'fid, drying and heating, so as to burn away the fiber, substantially as and for the purpose specified.

8. The process of metallizing with precious metals which consists in impregnating a fabric with a bromoformic solution of nitrated compounds of precious metals with ethyl sulfid, drying, heating so as to burn away the fiber, and welding the metallic structure obtained, substantially as and for the purpose specified; I

In testimony whereof I have hereunto/set my hand in' presence of two subscribing witnesses.

' RUDOLF LANGHANS.

Witnesses: v

WOLDEMAR HAUPT HENRY HASPER. 

